The present invention relates to an apparatus for producing a compact and efficient water cooling curtain for cooling moving metal sheets and belts. One or several water boxes are distributed along the entire length of a cooling track, each of these boxes are connected with water supply sources and each are provided with a narrow inlet or slit nozzle which is arranged across the direction of motion of the sheets or belts to be cooled. The cooling water is directed between the longitudinal walls of the slit nozzle and the water continuously exits therefrom so that a maximum laminar current of water flow is achieved.
The cooling requirements which relate to the output of water necessitates that the current flow, within the water curtain, be as laminar as possible, thereby contributing to stability, homogenity, and improvement of the desired cooling effect. To this end, it is known to provide one or several rectangular slit nozzles across the entire width of the goods to be cooled. The longitudinal walls of these nozzles are pivotal, thereby allowing a gradual adaptation of the cooling water current to individual operational conditions. The adjustment, in this manner, occurs such that the longitudinal walls are paired and are highly convergent with respect to each other. The exit openings of those slit nozzles for the cooling water are relatively narrow as compared to the entrance openings. Non-adjustable longitudinal walls have been provided with a circular or concave profile, in order to narrow the exit opening. In order to support the effect in the known water-cooling apparatus it is furthermore provided for wedge-shaped sliders of a convex-concave profile to mesh into the nozzle slit. See, for example, German reference DE-PS No. 22 35 063.
Furthermore, it is also known, for the providing of a compact and continuous water curtain for cooling to have the water strike the goods from a great height (see German reference DE-OS No. 28 04 982). In addition, it is known to insert, in a rectangular slit nozzle, the entrance opening of which has a considerably larger cross sectional area than the exit opening, additional sieve-type components having a plurality of adjacent converging conduits in the nozzle, so as to further reinforce the convergence effect.
The above concepts of converging slit nozzles for decreasing turbulence at the nozzle exit can be, to some extent, quite costly to install and can, in practice, only be realized at great relative expense.